wide area networking protocols.ppt

WideAreaNetworkingProtocols,天马行空官方博客：,Overview,1.0WideAreaNetworks2.0High-LevelData-LinkControlProtocol(HDLC)3.0Point-to-PointProtocol(PPP)4.0FrameRelay5.0IntegratedServicesDigitalNetwork6.0Dial-onDemandRouting(DDR),天马行空官方博客：,1.0WideAreaNetworks,1.1IntroductiontoWideAreaServices1.2DefiningWANTerms1.2WANConnectionTypes1.3WANProtocols,1.1IntroductiontoWideAreaServices,ToextendLANstootherLANsatremotesitesConnectingsitestogethersoinformationcanbeexchangedServiceprovidersleaseorsharetheiralreadyinstalledconnections,1.2DefiningWANTerms(WANServiceProviders),CustomerPremisesEquipment(CPE)EquipmentthatisownedandlocatedatthesubscriberspremisesDemarcation(demarc)TheplacewheretheCPEendsandthelocalloopportionoftheservicebegins(usuallyinthe“phone-closet”)LocalLoopConnectsthedemarctotheclosestswitchingoffice(CO)CentralOffice(CO)/PointofPresence(POP)Connectsthecustomerstotheprovidersswitchingnetwork.TollNetworkTheswitchesandfacilities,(trunks),insidetheWANproviders“cloud”.,Synchronousserial,Asynchronousserial,ISDN,Synchronousserial,1.3WANConnectionTypes,DedicatedLeasedlines(PointtoPointConnection)Apre-establishedWANcommunicationspathfromtheCPE,throughtheDCEswitch,totheCPEoftheremotesite,allowingDTEnetworkstocommunicateatanytimewithnosetupproceduresbeforetransmittingdata.,CircuitSwitchingSetsuplinelikeaphonecall.Nodatacantransferbeforetheend-to-endconnectionisestablished.Usedial-upmodemsandISDN.Itisusedforlow-bandwidthdatatransfers.,PacketSwitchingSharebandwidthwithothercompaniestosavemoney.Fornotconstantlydatatransmission(otherwiseusingleasedline),TelephoneCompany,ServiceProvider,Speedupto45Mbps,Low-bandwidthdatatransfers,Speedrangefrom56Kto2.048M,1.4WANProtocols,FrameRelayPacket-switchedtechnologywithDataLinkandPhysicalLayerspecificationProvideDynamic-bandwidthallocationandcongestioncontrolISDN(IntegratedServicesDigitalNetwork)VoiceandDatatransmissionoverexistingphonelinesHigherspeedthananalogdial-uplink;goodchoiceasabackuplinkLAPB(LinkAccessProcedure,Balanced)Aconnection-orientedprotocolattheDataLinklayerforusewithX.25Veryhighoverhead;onlyusediflinkisveryerrorproneHDLC(High-LevelDataLinkControl)DerivedfromSynchronousDataLinkControl(SDLC)createdbyIBMAconnection-orientedprotocolattheDataLinkLayer,lowoverheadEachvendorsHDLCisproprietaryfortheirequipmentPPP(Point-to-PointProtocol)Anindustry-standardprotocol,tocreatepoint-to-pointlinksbetweendifferentvendorsequipmentAllowauthenticationandmulti-linkconnections,runoverasyn.ortypethefollowingcommandsRouter(config-if)#EncapsulationhdlcEachvendorhasadifferentwayfortheHDLCprotocoltocommunicatewiththeNetworklayerprotocolNoauthentication,Bit-orientedprotocolsusesinglebitascontrolinformation(byte-orienteduseentirebyte),3.0Point-to-PointProtocol,3.1IntroductiontoPPP3.2Point-to-pointProtocolStack3.3LinkControlProtocol(LCP)ConfigurationOptions3.4PPPSessionEstablishment3.5PPPAuthenticationMethods3.6ConfiguringPPPonCiscoRouters3.7VerifyingPPPEncapsulation,3.1IntroductiontoPPP,AData-link,point-to-pointprotocolusedOverasynchronousserial(dialup)Oversynchronousserial(ISDN,Leasedline)LCP(LinkControlProtocol)tobuildandmaintaindata-linkconnectionsUsetotransportlayer-3packetsacrossaData-linklayerComponents:EIT/TIA-232-C(formerlyRS-232)physicallayerinternationalstandardforserialcommunicationHDLCAmethodforencapsulatingdatagramsoverseriallinksLCPAmethodofestablishing,configuring,maintaining,andterminatingthepoint-to-pointconnectionNCPEncapsulatingdifferentNetworklayerprotocolacrossaPPPdatalink,3.2Point-to-pointProtocolStack,PPP,ServiceProvider,TCP/IP,AppleTalk,PPPEncapsulation,TCP/IP,IPX,AppleTalk,IPX,3.3LinkControlProtocol(LCP)ConfigurationOptions,LCPoffersPPPthefollowingoptions:AuthenticationPAPprotocolsspanacrossOSIsPhysical,DataLinkandNetworklayersAlsousedforotherfunctions(e.g.alarmsystemforabuilding)whichdoesntneedmuchbandwidth,5.3BasicRateInterface(BRI)-2,SetupprocedureforaBRIcall:DchannelbetweenrouterandISDNswitchcomesupISDNswitchusestheSS7signalingtechniquetosetupapathtoaremoteswitchTheremoteswitchsetsuptheD-channellinktotheremoterouterTheBchannelsoflocalandremoteroutersarethenconnectedend-to-end,5.4PrimaryRateInterface(PRI),ProvidehighertransferrateMainlyuseinBusinessorPBX(PrivateBranchExchange)InNorthAmericaandJapanISDNPRIprovides23B(64K)+1D(64K)serviceTotalbitrateupto1.544MbpsInEurope,AustraliaISDNPRIprovides30B(64K)+1D(64K)serviceTotalbitrateupto2.048Mbps,5.5ISDNwithCiscoRouters,Routershouldhavebuilt-inNT1oranISDNmodemforISDNAccessWhenconfiguringISDNyoullneedtoknowthetypeofswitchwhatyourserviceproviderisusing(differentmanufacturerhasaproprietaryprotocolforsignaling)Needtoseewhichswitchestherouterwillsupportbyusingcommandisdnswitch-type?,5.6ISDNConfigurationTasks,Router(config)#isdnswitch-typeORRouter(config-if)#isdnswitch-typeRouter(config)#interfacebriSelectstheinterfaceforISDNBRIoperationRouter(config-if)#encapsulationppp|hdlcSelectsframingforISDNBRIRouter(config-if)#isdnspid1spid-numberldnSetsaBchannelServiceProfileIdentifier(SPID)requiresbymanyserviceprovidersRouter(config-if)#isdnspid2spid-numberldnSetsaSPIDforthesecondBchannelSpid-numberisprovidedbytheISDNprovidertoidentifyyouontheswitchLdn=localdialnumber,5.7ISDNConfigurationExample,ExampleRouterA(config)#isdnwitch-typebasic-nelRouterA(config)#intbri0RouterA(config-if)#encapppp(optional)RouterA(config-if)#isdnspid10865066101008650661RouterA(config-if)#isdnspid20865066201008650662,Theisdnswitch-typecommandcanbeconfiguredeitherin:GlobalconfigurationmodesettheswitchtypeforallBRIintherouterInterfaceconfigurationmodesettheswitchtypeforindividualinterface,6.0Dial-on-DemandRouting(DDR),6.1IntroductiontoDDR6.2ConfiguringDDR6.2aConfiguringStaticRoutes6.2bSpecifyingInterestTraffic6.2cConfiguringtheDialerInformation6.3OptionalCommands6.4VerifyingtheISDNOperation,Router1,CorporateIntranet,RemoteNetwork,Modem,PSTN,ISDN,Internet,Modem,Router1,6.1IntroductiontoDDR,Dial-on-demandrouting(DDR)isusedtoallowtwoormoreCiscorouterstodialanISDNdial-upconnectiononanas-neededbasis.DDRisonlyusedforlow-volume,periodicnetworkconnectionsusingeitheraPublicSwitchedTelephoneNetwork(PSTN)orISDN.ThiswasdesignedtoreduceWANcostsifyouhavetopayonaper-minuteorper-packetbasis.DDRworkswhenapacketreceivedonaninterfacemeetstherequirementsofanaccesslistdefinedbyanadministrator,whichdefinesinterestingtraffic.ThefollowingfivestepsgiveabasicdescriptionofhowDDRworkswhenaninterestingpacketisreceivedinarouterinterface:Routetothedestinationnetworkisdetermined.InterestingpacketsdictateaDDRcall.Dialerinformationislookedup.Trafficistransmitted.Callisterminatedwhennomoretrafficisbeingtransmittedoveralinkandtheidle-timeoutperiodends.,6.2DDRConfigurationTasks,ToconfigurelegacyDDR,youneedtoperformthreetasks:1.Definestaticroutes,whichdefinehowtogettotheremotenetworksandwhatinterfacetousetogetthere.2.Specifythetrafficthatisconsideredinterestingtotherouter.3.Configurethedialerinformationthatwillbeusedtodialtheinterfacetogettotheremotenetwork.,Commandsdefininginterestingtraffic,DialerGroup,S0orBRI0,CommandssetDDRcallparameters,Commandsdirectcallandtraffictogroupinterface,DDRinterface,6.2aConfiguringStaticRoutes,ToforwardtrafficacrosstheISDNlink,youconfigurestaticroutes(notdynamic)ineachoftherouters.KeepthefollowinginmindwhencreatingstaticroutesDDR:Allparticipatingroutersmusthavestaticroutesdefiningallroutesofknownnetworks.Defaultroutingcanbeusedifthenetworkisastubnetwork.AnexampleofstaticroutingwithISDNisshownbelow:RouterA(config)#iprouteRouterA(config)#iproute55bri0Thefirstlinetellstherouterhowtogettonetwork,whichisthrough.Thesecondlinetellstherouterhowtogetto.,6.2bSpecifyingInterestingTraffic,SpecifyinginterestingtrafficmeanstoconfiguretheroutertodeterminewhatbringsuptheISDNline.Anadministratorusingthedialer-listglobalconfigurationcommanddefinesinterestingpackets.Router(config)#dialer-listprotocolpermit|deny|list|Todefineadial-on-demandrouting(DDR)dialerlistfordialingbyProtocolAcombinationofaprotocolandapreviouslydefinedaccesslistUsethedialer-groupcommandtoassociateinterfacewiththedialerlistExampleshowingthecommandstoturnonallIPtraffic:Router(config)#dialer-list1protocolippermitRouter(config)#intbri0Router(config-if)#dialer-group1,6.2cConfiguringtheDialerInformation,Therearefivestepsintheconfigurationofthedialerinformation.1.Choosetheinterface.2.SettheIPaddress.3.Configuretheencapsulationtype.4.Linkinterestingtraffictotheinterface.5.ConfigurethenumbertodialbyusingthedialerstringcommandHereisanexampleofhowtoconfigurethefivesteps:Router(config)#intbri0Router(config-if)#ipaddressRouter(config-if)#encapsulationpppRouter(config-if)#dialer-group1Router(config-if)#dialerstring8350661ToconfigureaserialinterfaceorISDNinterfacetocalloneormultiplesitesortoreceivecallsfrommultiplesites,usethedialermapcommandRouter(config-if)#dialermapipnameRouter28350661,6.3OptionalCommands(1),Router(config-if)#dialermapnamehostnamespeed56/64broadcastdialer-stringDefineshowtoreachaDDRdestinationRecipientsprotocoladdress(Optional)Hostnameofremotesystem(Optional)LinespeedforTDMcircuit(Optional)Indicatesbroadcastsareforwarded(Optional)Phonenumberofnexthopsenttothedialingdeviceforinterestingtrafficdialermapmustbeusedwithdialer-groupcommand,6.3OptionalCommands(2),Router(config-if)#dialerwait-for-carrier-timeSpecifiestimetowaitforcarriertocomeupRouter(config-if)#dialerload-thresholdoutbound|inbound|eitherSpecifybandwidthondemandbysettingthemaximumloadbeforethedialerplacesanothercalltoadestinationInterfaceusedtodeterminewhethertoinitiateanothercallortodropalinktothedestination.Thisargumentrepresentsautilizationpercentage;itisanumberbetween1and255,where255is100%Thesecondoptionf